This invention relates generally to transistor packages, and particularly the invention relates to RF, microwave, and high-power transistor packages and transistors where high gain and maximum stability must be obtained.
FIG. 1A is an exploded perspective view of a conventional RF power transistor package including a ceramic substrate 2, transistor 3, cover 4, leads 5 extending from the substrate 2, and wire bonds 6 connecting the transistor to the leads.
FIG. 1B is a plan view of the lead structure for the RF power transistor package. The leads are bonded to and extend from the ceramic substrate shown by dotted line 10. The transistor is mounted on a pad or island 12 centrally disposed (approximately) on the substrate and electrically isolated from the leads. An input lead 14 is positioned between ground leads 16, 18 on one side of the island 12, and an output lead 20 is positioned between the ground leads 16, 18 on the opposite side of the island 12. Wire bonds selectively connect the transistor emitter, base, and collector to the input, output, and ground leads. This lead frame has been in use for many years, but a major drawback of the lead structure lies in the current path length between the transistor ground leads.